Spatial depolarization of light from the bulks: electromagnetic prediction

Zerrad, Myriam; Tortel, Hervé; Soriano, Gabriel; Ghabbach, Ayman; Amra, Claude

doi:10.1364/oe.23.008246

Cited by 11 publications

(8 citation statements)

References 27 publications

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“…Thick anisotropic substrates have formerly provided solutions to depolarize light [21,[37][38][39][40][41][42][43]. The technique consists in using a bulk material with a similar cutting edge κ (see Fig.…”

Section: Depolarizationmentioning

confidence: 99%

Broadband loss-less optical thin-film depolarizing devices

Ailloud¹,

Zerrad²,

Amra³

2018

Opt. Express

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For some space applications, sensors are sensitive to light polarization and can only be properly calibrated with non-polarized light. Here we propose new optical devices which allow to depolarize light in a spatial process. These devices are thin film multilayers which exhibit polarimetric phase variations in their plane. A zero spatial polarization degree can be reached with high accuracy in a controlled bandwidth.

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Section: Depolarizationmentioning

confidence: 99%

Broadband loss-less optical thin-film depolarizing devices

Ailloud¹,

Zerrad²,

Amra³

2018

Opt. Express

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“…(6). As we study the case of monochromatic illumination and temporally stable fields, the only contributions to the C 2 value are the experimental noises, that are neglected here, and the spatial depolarization [16,17,18,19]. The spatial depolarization appears due to the sampling on the pixel surface of a continuously varying polarization map.…”

Section: Spatial Depolarization Estimationmentioning

confidence: 99%

“…We then study the impact of the imaging point spread function on polarimetry. Finally we propose a study of the spatial depolarization [16,17,18,19], which appears because of the spatial sampling by an observer of a continuous space-variant polarization map.…”

Section: Introductionmentioning

confidence: 99%

Simulation of polarized optical speckle fields: effects of the observation scale on polarimetry

Dupont¹,

Orlik²

2016

Opt. Express

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In this paper, we propose the simulation of polarized speckle fields using the Stokes formalism, which allows the description of partially polarized electromagnetic waves. We define a unique parameter which determines the partial decorrelation of the involved fields, allowing to simulate the polarized speckles produced by all types of scatterers, from simple to multiple scatterers. We validate this model by comparison with experimental measurements. We use that simulation model to study the impact of the imaging device parameters on polarimetric measurements: first we emphasize a limit of resolution on retardance measurements, then we study the spatial depolarization, which appears when an observer is measuring any space-variant polarization map.

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“…These features make this method attractive to many applications, which require fast and non-destructive sampling. Combined with polarization, speckle image analysis techniques provide new parameters describing media properties (such as scattering or absorption) [ 16 , 17 , 18 , 19 , 20 , 21 ] which makes this method very attractive for precision agriculture applications.…”

Section: Introductionmentioning

confidence: 99%

A New Optical Sensor Based on Laser Speckle and Chemometrics for Precision Agriculture: Application to Sunflower Plant-Breeding

Ryckewaert¹,

Heran²,

Faur³

et al. 2020

Sensors

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New instruments to characterize vegetation must meet cost constraints while providing accurate information. In this paper, we study the potential of a laser speckle system as a low-cost solution for non-destructive phenotyping. The objective is to assess an original approach combining laser speckle with chemometrics to describe scattering and absorption properties of sunflower leaves, related to their chemical composition or internal structure. A laser diode system at two wavelengths 660 nm and 785 nm combined with polarization has been set up to differentiate four sunflower genotypes. REP-ASCA was used as a method to analyze parameters extracted from speckle patterns by reducing sources of measurement error. First findings have shown that measurement errors are mostly due to unwilling residual specular reflections. Moreover, results outlined that the genotype significantly impacts measurements. The variables involved in genotype dissociation are mainly related to scattering properties within the leaf. Moreover, an example of genotype classification using REP-ASCA outcomes is given and classify genotypes with an average error of about 20%. These encouraging results indicate that a laser speckle system is a promising tool to compare sunflower genotypes. Furthermore, an autonomous low-cost sensor based on this approach could be used directly in the field.

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Spatial depolarization of light from the bulks: electromagnetic prediction

Abstract: Abstract:The spatial depolarization of light emitted by heterogeneous bulks is predicted with exact electromagnetic theories. The sample microstructure and geometry is connected with partial polarization.

Cited by 11 publications

References 27 publications

Broadband loss-less optical thin-film depolarizing devices

Broadband loss-less optical thin-film depolarizing devices

Simulation of polarized optical speckle fields: effects of the observation scale on polarimetry

A New Optical Sensor Based on Laser Speckle and Chemometrics for Precision Agriculture: Application to Sunflower Plant-Breeding

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